- Numerical ages
- Age models are based on age-depth plots for every hole, that
were constructed with the help of an interactive graphics application
called Age-Depth Plot (ADP). This program was originally
written by David Lazarus in True Basic programming language and
designed for the 68 generation of Macintosh. Meanwhile, ADP
was first recompiled for usage on PowerMacintosh (ADP PPC).
In order to provide platform independent versions, ADP
was re-written in 4D, and can be downloaded from this server
as standalone applications for MacOs and PC/NT operating systems.
All versions can be downloaded
from the NEPTUNE-online II server.
- With ADP age-depth
diagrams can be constructed interactively by visual graphical
correlation. Input data are the vertical distribution of first
appearance (FAD) or last appearance datums (LAD) of stratigraphic
events along a core. The program allows to plot the datums in
age-depth scatter diagram and then to manually interprete a line
segments of most reasonable fit. The control points of the line
segments can be exported as a "line of correlation"-
(LOC) file in ascii text format.
- All datums of Cenozoic events follow the integrated chronology
et al. (1995). If necessary the age assignments for the included
microfossil datums (i.e. planktonic foraminifera, coccoliths,
radiolaria, diatoms, bolboforma) were magnetically converted
to the Cande
and Kent (1995) magnetic polarity time scale.
- An extended age model collection for DSDP and ODP holes was
prepared, using oxygen isotope events, marine strontium isotope
stratigraphy and bolboforma stratigraphy. For the Pleistocene
to Holocene Period oxygen isotope stage boundaries and events
were included as well. For this the nomenclatures of isotope
events of Prell
et al. (1986) and Ruddiman et al. (1989) were applied. Oxygen
isotope datums were magnetically converted to the Cande and Kent (1995) magnetic polarity time
scale. The datums of events 1.1 through 16.23 were taken from
et al. (1984), those from event 17.1 on from Shackleton et al. (1990), and the ogygen
isotope chronology was extended back to the Early Pleistocene
using the O-isotope stratigraphy of Williams
et al. (1988). Sr 87/86 ratios were integrated where possible,
using the Marine Sr Isotope Curve of Howarth and McArthur (1997). Ages of marine
Sr 87/86 ratios between 0 and 7 Ma have also been converted to
and Kent (1995) magnetic polarity time-scale. The bolboforma
stratigraphy follows that of Spiegler and von Daniels (1991), that was
extended and calibrated to the Cande
and Kent (1995) time-scale.
- For the construction of age the models presented here the
FAD and LAD intervals of each stratigraphic event, as well as
the necessary information of the depths of the core-tops, core-lengths
and recovery were taken from the respective Initial and Scientific
Reports of the DSDP and ODP and the coring summaries therein.
The names and ages of stratigraphic events per microfossil group
per geographic area are listed in text formats in Excel spreadsheets
(=templets). These templets formed the basis to compile the age-depth
information of the FADs and LADs of stratigraphic events. See
links leading to Templets
(Mac or PC archives).
- The data containing the actual stratigraphic distribution
of microfossils or events per site (only FADs and LADs) are stored
in single ascii text files. See links
directing to Bstrat files (Mac or PC archives).